Gastric and Sigmoid Colonic Metastases from Breast Cancer: A Case Report and Literature Review

Abstract

Background Breast cancer has become the most commonly diagnosed cancer in the world, but gastrointestinal metastasis from breast cancer is rare. It is extremely rare to have both gastric and sigmoid colonic metastases in one case. For patients considered gastric or colon carcinoma who have a history of breast cancer, it is difficult to identify the origin. Even so, clinicians still need to make accurate diagnosis due to great different treatment principles. Case presentation: We present a case that diagnosed as metachronous gastric and sigmoid colonic metastases from invasive lobular carcinoma of the breast. On June 7, 2021, A 65-year-old female patient came to our department complained recurrent abdominal discomfort for one week. Gastroscopy in our hospital suggested that there was a superficial depressed lesion (type IIC) in her gastric antrum, while pathology indicated poorly differentiated carcinoma. Combined with the patient's breast cancer history and immunohistochemical results, we accurately diagnosed her as gastric metastasis of breast cancer rather than primary gastric cancer. During systematic treatment progress, sigmoid colonic metastasis was detected with colonoscopy on September 19, 2022. Up to May 2023, the patient is still alive with an overall survival greater than 23 months. Conclusions Gastrointestinal metastasis of breast cancer is rare in clinical work, but the incidence of autopsy is up to 15–16%. This phenomenon suggests that some patients with advanced breast cancer have not been accurately diagnosed, which may lead them to receive inappropriate treatment. At present, estrogen/progesterone receptor (ER/PR), GATA binding protein-3 (GATA-3), cytokeratin 7/20 (CK7/20), gross cystic disease fluid protein-15 (GCDFP-15) and mammaglobin are the most diagnostic immunohistochemical markers.